Re: prop question
- From: dougmc@xxxxxxxxxx (Doug McLaren)
- Date: Sun, 30 Oct 2005 06:09:12 GMT
In article <1130651229.677790.321200@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
seany1124 <seany1124@xxxxxxxxxxx> wrote:
| what effect would switching a 10/6 prop to a 11/7 have on flight
| characterisitcs? my guess is none!(keeping engine the same,, say..46
| 2c)
|
| in theory, you should get better climb, and higher top end speed,
| however, since RPM would fall, all benefits would be neutralized and
| you simply get a slower running engine. agree?/disagree?
It depends on many factors.
Your engines have a `sweet spot' where the run the best and produce
the most power. Give it a smaller prop, and it'll run faster, but
will produce less thrust (Note that this may, or may not, give you a
higher top speed.). Give it a larger prop, and it'll run slower and
produce less thrust. (Or, it may give you a bit more thrust, but a
lower top speed.)
There's lots of other factors too -- the `dragginess' of the airframe,
the altitude you fly at, what kind of flying you do, the fuel you use,
and of course the exact engine you've got.
Actually, if things did equal out like you said (and for some
combinations, they sort of do) a slower running engine may be a good
thing -- it may last longer, and it'll be quieter.
You may also find that your climb improves, but your high end speed
actually decreases. Or vice versa. It all depends.
Electrics make this sort of `what if' a whole lot simpler, since
things like motocalc can calculate all of this with good accuracy.
--
Doug McLaren, dougmc@xxxxxxxxxx
Talk is cheap because supply exceeds demand.
.
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